Conventionally, the saddle-ride type vehicle typified by the motorcycle for a rider to sit and drive while straddling a seat is provided with a power transmission device. The power transmission device transmits a driving force generated by an engine (a prime mover) to driving wheels. The power transmission device is a mechanical device which changes and transmits a rotational speed of a crankshaft of the engine to the driving wheels while being connected to and disconnected from the crankshaft. The power transmission device is mainly composed of a clutch and the transmission.
Here, the clutch is a mechanical device which transmits a rotational driving force of the crankshaft to the transmission side while being connected to and disconnected from the crankshaft of the engine. The transmission is a mechanical device which changes the rotational speed of the crankshaft of the engine by a plurality of shift stages formed by a combination of a plurality of gears, and transmits the speed to the driving wheel side.
In this case, the transmission is configured to change the plurality of shift stages by the rotational driving force of the shift actuator including an electric motor. For example, the saddle-ride type vehicle disclosed in the following Patent Literatures 1 and 2 is configured such that the shift actuator is provided in the vicinity of a cylinder block of the engine.